For soil nails a new certification (Dywidag-Bodennägel, August 2013) is available which is based on the analysis with partial safety factors acc. to Eurocode 7.
Within this certification there is a number of changes in the analysis apporach:
- The earth pressure on the nail wall has to be calculated in Design Approach 2 (instead of Design Approach 2 or 3 alternatively acc. to DIN 1054:2010)
- For the earth pressure the cohesion of the soil is considered, in addition we apply minimum earth pressure with a substitutive angle of internal friction of 40°
- The reduction of the earth pressure with a factor of 0.85 and the redistribution into a rectangle are only applied to the earth pressure from permanent actions
- The earth pressure inclination should be defined parallel to the soil nails
In the new version 4.3 of program DC-Nail these new approaches are used automatically when selecting Eurocode 7 as the analysis standard.